As the COVID-19 pandemic unfolds, we often hear about the critical need for N-95 masks (also called N-95 respirators). Did you know these vital pieces of personal protective equipment are almost entirely made from petroleum-based products? The very fine filtering necessary to prevent infection is made possible by polymers like polypropylene and other petroleum derivatives – basic cloth masks don’t do the job.
An N-95 mask is a particulate-filtering device that fits and seals over the mouth and nose. The N-95 designation means the filtering portion of the mask meets the N-95 standard of the U.S. National Institute for Occupational Safety and Health air filtration rating, meaning it filters at least 95 per cent of airborne particles greater than 0.3 microns in size (for comparison, a human red blood cell is about five microns in diameter). These masks provide protection against particulates, but not gases or vapours.
In addition to medical applications, N-95 masks have been commonly used by workers exposed to fine dust and other airborne particles. As researchers learn more about the COVID virus, it’s becoming clear that tiny droplets from speaking, coughing, sneezing and even breathing are the main means of virus spread. Therefore, to protect the safety of health-care workers and others likely to come in contact with the virus, N-95 masks are essential.
How it’s made
Virtually all the components of an N-95 mask are made from petroleum products, and even the non-petroleum parts – steel and aluminum – require oil or natural gas as part of their manufacturing process.
N-95 masks offer multiple ways to keep particles from passing through. Interlaced layers of polypropylene fibres present a tortuous maze in which particles tend to get stuck – a mechanism called’ inertial impaction.’ Another mechanism called ‘diffusion’ helps keep extremely small particles from passing through because the filter causes these particles to move in random directions, colliding with each other and with filter fibres. Finally, during manufacture the mask filter receives a small electric charge that traps particles through a process called ‘electrostatic attraction’ – essentially static electricity, the same way a balloon rubbed on your hair or sweater will stick to a wall.
U.S. manufacturer 3M is a major source of N-95 masks but in early April Ontario premier Doug Ford announced that an automotive parts manufacturer in that province would be shifting production to begin making masks. The federal government has also called on Canadian manufacturers to develop, test and produce N-95 masks. Any such product requires Health Canada approval.
And no, you cannot make an N-95 mask at home. An effective N-95 mask can only be made using the correct materials – derived from petroleum.